1. Field of the Invention
This invention relates to fluid pumps and in particular to high pressure fluid pumps such as fuel injection pumps for automotive engine application.
2. Description of Background Art
A large number of different pumps has been developed for uses such as providing fuel in automotive and other engine applications. Illustratively, a fuel pump is shown in U.S. Pat. No. 1,984,614 of George R. Welch wherein a piston is utilized to effect the pumping action. The patentee teaches that a certain amount of leakage is sure to occur between the piston and wall of the barrel and provides a channel for returning the fuel to the chamber above the piston.
Claude Sauzedde, in U.S. Pat. No. 1,999,211, shows a compressor utilized in a hydrostatic braking system.
Samuel G. Eskin shows a regulating device in U.S. Pat. No. 2,310,519 wherein a plunger is associated with a body of flexible or resilient material for controlling movement of the plunger. The plunger is moved by extension of liquid in a bulb portion of the device, the movement being controlled by the resilient body.
Cecil W. Smith, in U.S. Pat. No. 2,342,906, shows a pump having a cup-shaped elastic member for protecting the piston so that the pump may be used with abrasive fluids.
A diaphragm pump is shown by Erwin F. Loweke in U.S. Pat. No. 2,354,958 wherein the diaphragm is provided with an annular skirt mounted and bonded to a ring which, in turn, is bolted to the pump cylinder.
In U.S. Pat. No. 2,690,295, Henry J. Rand shows an air pump having a diaphragm including a flat circular disc with integral annular and peripheral flanges extending at approximately right angles from the underface of the disc and a ring-shaped member extending from its upper face. The ring is provided with an eccentrically driven member to reciprocate the diaphragm for alternately expanding and contracting the pumping chamber.
Orro Holm shows, in U.S. Pat. No. 2,712,793, a pump construction utilizing a piston provided with a frustoconical resilient body. By causing a different conicity of the piston and the chamber wall, the resilient body is mechanically sealingly secured therebetween without the need for adhesion means such as vulcanization. In one form, the resilient body includes a disc portion overlying the end of the piston.
Henry A. Berliner, in U.S. Pat. No. 2,791,969, shows a reciprocating pump wherein a hollow cylindrical extensible resilient member is provided within a cylindrical body member and includes a closed end defining with the body member a pump chamber. A rod extends into the resilient member and includes an enlarged end portion bearing against the closed end of the resilient member. The rod is adapted to be reciprocated so as to move the closed end of the resilient member correspondingly to expand and contract the pumping chamber.
In U.S. Pat. No. 2,843,151, Frederick A. Greenawalt shows a hydraulic power element wherein a Teflon plug interconnects a resilient member and an actuating plunger. Pressure acting on the resilient member is transmitted through the plug to the plunger for actuating a control element, such as the control mechanism of the thermostatic device. The fluid pressure is introduced into a second resilient member defining an expansible chamber and abutting the first resilient member.
In U.S. Pat. No. 2,869,585, Max P. Baker shows a flexible diaphragm for use in a pump or the like. The diaphragm has marginal edges thereof shaped to form a seal with portions of the pump when that edge is pressed into sealing engagement by a metallic spring member with the pump body.
A variable rate positive displacement pump is shown in U.S. Pat. No. 2,871,846 of John Zimmerman. The pump is adapted for use as a fuel injection pump and includes a pair of cylinders at opposite sides of a driving eccentric or cam. A plug of resilient material is disposed in a cylinder and engaged by the piston with one end of the plug having a cavity forming a pumping chamber. The reciprocating movement of the piston causes the plug to be periodically compressed so as to vary the volume of the pumping chamber to produce the desired pumping action. The plug engages the walls of the cylinder very tightly to provide a liquid-type seal.
Another pump for use in an injection system is shown in U.S. Pat. No. 2,913,991 of John Dolza et al. This pump is generally similar to that of the Zimmerman pump. In the Dolza et al structure, the resilient plug is maintained under compression at all times so as to maintain a seal thereof with the wall of the cylinder. The rotation of the actuating eccentric causes the plug to expand and contract so as to correspondingly move a plunger so as to vary the capacity of the pumping cavity.
Earl R. Pierce shows, in U.S. Pat. No. 2,929,332, a fuel injection pump wherein a resilient plug is disposed at one end of the cylinder which is compressed so that it will positively engage the end of the piston, the sidewalls of the cylinder, and the end wall of the cylinder. A pumping chamber is formed in an end of the cylinder by a recess in either the cylinder or the resilient plug. Inward movement of the piston compresses the plug and causes the volume of the pumping chamber defined by the recess to decrease and force the liquid therefrom. When the piston moves outwardly, the plug expands and draws a fresh supply of fluid into the chamber.
Lloyd G. Porkert shows a pump unit in U.S. Pat. No. 2,962,974 having a collapsible capsule bonded to a cylinder head and enclosing an expansible chamber of the pump unit.
A variable volume pump is shown in U.S. Pat. No. 3,019,738 of Joseph Zubaty. The pump utilizes a diaphragm actuated by plungers, in turn actuated by a cam mechanism. Each plunger is provided with an individual diaphragm forming one wall of the pump chamber. The side of the diaphragm forming the pump chamber is concave and the head of the pump plunger which contacts and flexes the diaphragm is rounded.
William E. Baker shows a pressure responsive actuator in U.S. Pat. No. 3,078,876 wherein the plunger acts through an actuating member having a conical portion received in a force-transmitting body molded into a recess in the housing. A cup-shaped insert is in bonded relation with the wall of the housing recess. The force-transmitting member is formed of a suitable elastomeric material. The insert may be formed of Teflon. The insert bears against a loosely held metal disc.
Edward A. Cohen et al show a method of constructing an expulsion tank in U.S. Pat. No. 3,471,349 wherein a bladder material is sprayed on an inner surface of a tank segment with a band of bonding material along an inner surface thereof. The cured bladder is separated from the interior surface of the tank segment leaving the edge surface retained by the band of bonding material at the inner surface of the tank segment. Thus, the structure defines a pair of chambers separated by the bladder.
Robert H. Welker shows, in U.S. Pat. No. 3,945,770, a high pressure pump having a resilient plug captured between two nonyieldable members. A dished out portion of the resilient plug is contacted and sealed to define a closed chamber at the dished portion which varies in size as the nonyieldable members are relatively moved.
Abduz Zahid, in U.S. Pat. No. 4,045,861, shows a method of forming a pressure accumulator wherein the mouth of the deformable separator or bladder of the pressure accumulator is molded to one end of the cylindrical portion of the supporting member. The supporting member and bladder are inserted into the open end of a cylindrical casing. The cylindrical portion is fused to the inner surface of the casing.
Thus, the prior art shows a wide range of different fluid control or operating devices wherein deformable members are sealingly secured to an outer housing or body member and suitably moved so as to provide pump or actuating devices.